21046447 has 2 divisors, whose sum is σ = 21046448. Its totient is φ = 21046446.

The previous prime is 21046429. The next prime is 21046463. The reversal of 21046447 is 74464012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21046447 - 2¹¹ = 21044399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21046477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10523223 + 10523224.

It is an arithmetic number, because the mean of its divisors is an integer number (10523224).

Almost surely, 2^21046447 is an apocalyptic number.

21046447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21046447 is an equidigital number, since it uses as much as digits as its factorization.

21046447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5376, while the sum is 28.

The square root of 21046447 is about 4587.6406790419. The cubic root of 21046447 is about 276.0956706423.

The spelling of 21046447 in words is "twenty-one million, forty-six thousand, four hundred forty-seven".